bug#3207: 23.0.93; x-display-planes is incorrect in NS port

When starting up NextStep Emacs compiled from CVS HEAD, the old XPM  
splash image is used, rather than the new PNG.

This appears to be caused by (display-planes) reporting an eight-plane  
display. This is almost certainly incorrect.

Looking deeper, (display-planes) calls (x-display-planes), in nsfns.m.  
I don’t see anything obviously wrong, but it’s reporting that I have  
an 8-plane display when it’s 24-plane. Evaluating (x-display-color- 
cells) produces the correct value: 16777216, indicating a 24-bit  
display.

In GNU Emacs 23.0.93.1 (i386-apple-darwin9.6.0, NS apple-appkit-949.43)
  of 2009-05-04 on neutron.local
Windowing system distributor `Apple', version 10.3.949
configured using `configure  '--with-ns''

Important settings:
   value of $LC_ALL: nil
   value of $LC_COLLATE: nil
   value of $LC_CTYPE: nil
   value of $LC_MESSAGES: nil
   value of $LC_MONETARY: nil
   value of $LC_NUMERIC: nil
   value of $LC_TIME: nil
   value of $LANG: nil
   value of $XMODIFIERS: nil
   locale-coding-system: nil
   default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
   diff-auto-refine-mode: t
   erc-track-mode: t
   erc-track-minor-mode: t
   erc-spelling-mode: t
   erc-ring-mode: t
   erc-pcomplete-mode: t
   erc-netsplit-mode: t
   erc-match-mode: t
   erc-button-mode: t
   erc-fill-mode: t
   erc-autojoin-mode: t
   erc-irccontrols-mode: t
   erc-noncommands-mode: t
   erc-readonly-mode: t
   erc-scrolltobottom-mode: t
   goto-address-prog-mode: t
   light-symbol-mode: t
   hl-line-mode: t
   eldoc-mode: t
   which-function-mode: t
   yas/minor-mode: t
   ime-bindings: t
   shell-dirtrack-mode: t
   show-paren-mode: t
   recentf-mode: t
   iswitchb-mode: t
   cua-mode: t
   auto-insert-mode: t
   tooltip-mode: t
   mouse-wheel-mode: t
   menu-bar-mode: t
   file-name-shadow-mode: t
   global-font-lock-mode: t
   font-lock-mode: t
   blink-cursor-mode: t
   global-auto-composition-mode: t
   auto-composition-mode: t
   auto-encryption-mode: t
   auto-compression-mode: t
   size-indication-mode: t
   column-number-mode: t
   line-number-mode: t
   transient-mark-mode: t
   abbrev-mode: t

Recent input:
i s p l a y - l <backspace> p l a n e s C-e C-x C-e
C-x o C-n C-p C-p M-m C-p C-p M-m C-n C-n C-f C-f M-m
C-x o M-b M-d c o l o r - p C-e C-x C-e C-x o C-n C-n
M-m C-p C-f C-f C-f C-x o C-a C-k <down-mouse-1> <mouse-1>
<down-mouse-1> <mouse-1> <switch-frame> l e o <tab>
SPC L o o k s SPC l i k e SPC N S SPC g e t s SPC t
h e SPC X P M SPC b e c a u s e SPC M-( d s i a p l
y <M-backspace> d i s p l a M-b C-b C-b C-k SPC i t
SPC t h i n k s SPC i t SPC h o <backspace> <backspace>
o n l y SPC h a s SPC 9 <backspace> 8 - b i t SPC c
l o l C-x C-g <switch-frame> C-h f d i s p l <tab>
- l <backspace> <backspace> p l <tab> <return> <switch-frame>
<backspace> <backspace> <backspace> o l o r SPC f o
r SPC s o m e SPC r e a s o n , <return> <switch-frame>
<down-mouse-1> <mouse-movement> <mouse-1> <help-echo>
<help-echo> <down-mouse-1> <mouse-1> <down-mouse-1>
<mouse-1> <switch-frame> <switch-frame> <down-mouse-1>
<mouse-1> <help-echo> <switch-frame> <switch-frame>
C-x b <return> <help-echo> <down-mouse-1> <mouse-1>
<down-mouse-1> <mouse-1> <down-mouse-1> <mouse-1> <down-mouse-1>
<mouse-1> M-( l e t SPC M-( M-( f a n c e y <backspace>
<backspace> y M-/ M-/ SPC M-" s p l a s h . p n g C-e
C-b <return> C-x o C-x o M-( f a n c y - s p l a s
h - h e a d C-e C-x C-e <help-echo> <down-mouse-1>
<mouse-1> <menu-bar> <help-menu> <send-emacs-bug-r
eport>

Recent messages:
8
Evaluating...
Mark set
t
Type C-x 4 C-o RET to restore the other window.
Scanning for dabbrevs...100%
Expansion found in 'startup.el.gz'
Evaluating...
Mark set
nil